It has been previously proposed to prepare tris-(.beta.-hydroxypropyl) isocyanurate by reaction of cynauric acid with an alkylene oxide. Inasmuch as cyanuric acid is a solid at the reaction temperature, the reaction is carried out in an inert solvent or vehicle such as dimethyl formamide (see French Patent Specification No. 1,451,000), a lower alcohol or an ether (see German Patent Specification No. 1,670,214) or benzene. The known reaction is furthermore effected in the presence of an acid or basic catalyst, most generally a strongly basic catalyst such as a tertiary amine or alkali hydroxide.
This known method of preparation, however, has the disadvantage that the solvent or vehicle, as well as traces of the catalyst, must be removed from the reaction product upon completion of the reaction. Furthermore, the product is obtain in the solid state, and in order to be used as a polyol in the preparation of polyurethane, it must be again dissolved in the other reactants.
It is an object of the present invention to provide a process for the preparation tris-(.beta.-hydroxypropyl) isocyanurate by the reaction of cyanuric acid with propylene oxide without the need for the presence of a catalyst. It is a further object of this invention to provide a process whereby the reaction product is obtained in a form directly usable as a polyol in the preparation of polyurethane without the need for separation and/or redissolution of the solid product.